Methods of placing large bore aspiration catheters

ABSTRACT

A methods of placing large bore aspiration catheters is disclosed. The method of removing a vascular obstruction includes the steps of transvascularly advancing a distal end of an aspiration catheter into proximity with an obstruction, activating a low flow, detection mode of aspiration through the catheter, and thereafter activating a momentary control to activate a high flow, aspiration mode of operation and draw obstructive material into the distal end of the access catheter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Patent Application No. 63/044,511, filed Jun. 26, 2020,the entirety of which is hereby incorporated by reference herein. Thisapplication is a continuation-in-part of U.S. patent application Ser.No. 17/125,723, filed Dec. 17, 2020, which claims the priority benefitunder 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No.62/950,058, filed Dec. 18, 2019 and U.S. Provisional Patent ApplicationNo. 63/064,273, filed Aug. 11, 2020, the entireties of which are herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

Thrombotic restrictions and occlusions within a patient's blood vesselsare a significant medical problem and often require intervention toremove these restrictions and blockages to restore health to patients.While applicable to a wide range of vascular applications in both thearterial and venous systems, including a variety of small vessels, thefollowing background illuminates the problems primarily through theexample of patients suffering with Pulmonary Embolisms.

Venous thromboembolic disease (VTE) is a worldwide crisis. There areover 10 million cases of deep vein thrombosis (DVT) and pulmonaryembolism (PE) diagnosed globally per year, with 1 million casesoccurring in the United States and over 700,000 in France, Italy,Germany, Spain, Sweden, and the United Kingdom combined each year. Thereare approximately 60,000 to 100,000 deaths from PE in the United Stateseach year. DVT and PE are part of the same continuum of disease, withover 95% of emboli originating in the lower extremities. When PE occurs,the severity depends on the embolic burden and its effect on the rightventricle as well as underlying cardiopulmonary comorbidities. Death canresult from the acute increase in pulmonary artery (PA) pressure withincreased right ventricular (RV) afterload and dysfunction.

Patients with high-risk pulmonary embolism (PE) were treated primarilywith thrombolytic therapy delivered systemically or more locally throughCatheter Directed Thrombolytics. These approaches result in multiplecatheterization lab visits, lengthy hospital stays and often lead tobleeding complications. Newer approaches to PE treatment include singlesession thrombectomy treatments without the use of thrombolytics. Thesethrombectomy treatments include delivering a catheter into the PA toremove the thrombus through aspiration, and secondary tools may alsomacerate or disrupt the thrombus prior to aspiration. While thrombectomyresults in fewer bleeding complications and reduced hospital stayscompared to thrombolytics, there is much to be improved upon given thechallenges of the procedure itself, including the ability to capture abroad spectrum of thrombus types and reduce the total volume of bloodloss during the procedure.

The thrombectomy catheter is introduced through an introducer puncturein a large diameter vein. A flexible guide wire is passed through theintroducer into the vein and the introducer is removed. The flexibleguidewire provides a rail for a flexible guide catheter to be advancedthrough the right atrium into the right ventricle and into the pulmonaryartery. The flexible guidewire is removed and replaced with a stiffguidewire. The large diameter thrombectomy catheter with support dilatoris then advanced over the stiff guidewire to the pulmonary artery andthe dilator is removed. If the large diameter thrombectomy catheter isnot successful in accessing or aspirating thrombus in a more distalportion of the vessel, a smaller diameter catheter may be insertedthrough the large diameter catheter.

In addition, peripheral arterial occlusive (PAO) disease occurs in morethan 4% of individuals over age 40 and markedly increases in incidenceafter the age of 70. Acute PAO is usually due to thrombosis of theperipheral vasculature and is associated with a significant risk of limbloss. In order to preserve the limb, therapy for acute PAO centers onthe rapid restoration of arterial patency and blood flow such as throughmechanical thrombectomy in procedures similar to those described above.

Clot aspiration using certain commercial vacuum-assisted thrombectomysystems may sometimes need to be terminated due to the risk of excessiveblood loss by the patient, especially when using large aspirationcatheters. During aspiration thrombectomy, when the catheter tip fallsout of contact with the thrombus or other occlusive material, the tip isexposed to healthy blood and full flow of blood through the catheterensues. Under such conditions, the total volume of blood loss isexcessive, and in some cases, may result in premature termination of theprocedure. For example, during a procedure when the catheter entershealthy blood and full aspiration flow ensues, the blood loss rate canbe on the order of 30-40 cc per second with an 24 French size catheter.With a maximum tolerable blood loss on the order of about 500 mL, thecatheter cannot run in unrestricted mode for more than approximately 10to 15 seconds. The aggregate blood loss may reach an unacceptable levelbefore sufficient clot is removed.

SUMMARY OF THE INVENTION

There is provided in accordance with one aspect of the present inventiona first vacuum aspiration system, such as for aspirating a targetmaterial such as an obstruction from the vascular system. The systemcomprises a housing, a fluid flow path extending through the housing,and a chamber for capturing and storing removed material. A firstcatheter is in fluid communication with the flow path, and a connectoris configured to place a source of aspiration (vacuum) in communicationwith the flow path. A flow regulator is configured to regulate fluidflow through the flow path. One or two or more operator actuatedcontrols are configured to toggle the flow regulator in response to theoperator's initiation, between a default, low flow mode, and amomentary, operator initiated high flow mode. The same control or aseparate control may be provided to toggle aspiration between an offmode and an on mode.

The system further comprises a side wall containing the flow path, andan optically transparent window in the side wall. At least a portion ofthe side wall may be in the form of an optically transparent tube.

The flow regulator may comprise a variable sized constriction in theflow path. The flow regulator may comprise a flexible flow path sidewall or tube and an actuator configured to compress the flexible tube.Alternatively, the flow regulator may comprise an adjustable aperturesuch as an iris or a valve, or a valve that toggles the flow pathbetween a low flow (e.g. low diameter) path and a high flow (e.g. highdiameter) path. Alternatively, the flow regulator may comprise tubinghaving a length and inside diameter selected to achieve a desired flowregulation.

The housing may further comprise a port, in communication with the firstcatheter, to guide a second, smaller catheter through the housing andinto and through the first catheter. A hemostasis valve may be carriedby the housing, in communication with the port.

The system may further comprise a reservoir for receiving thrombus andblood retrieved through the first catheter. The reservoir includes afilter for separating clot from blood, and a window to allow visualobservation of the clot that has accumulated on the outside surface orinside surface of the filter. In one implementation, the filtercomprises a tubular membrane spaced radially inwardly from an outertransparent tubular wall, to define an annular clot receiving chambertherebetween. Fluid flow during aspiration may be in the direction fromthe clot receiving chamber radially inwardly through the membrane. Atleast a portion of the reservoir may be releasably carried by thehousing.

The housing may additionally be provided with an infusion port, forproviding communication with an infusion lumen extending axially throughthe first catheter to an effluent port at the distal end of thecatheter. The infusion lumen may be used to infuse a volume of an activemedium such as a thrombolytic drug, or introduction of contrast agent toenable fluoroscopic visualization of the vasculature. Alternatively, theinfusion lumen may be used to infuse a volume of saline, to facilitateflushing the catheter and/or dilute the contrast agent, and/or to dilutethe aspirated blood thereby minimizing the total blood loss as a resultof the procedure. The lumen can also be utilized to measure bloodpressure at the distal end of the catheter.

The system may additionally be provided with a reinfusion circuit fordirecting filtered blood from the reservoir through a reinfusion pathwaythrough the housing and into communication with a reinfusion port. Thereinfusion port is configured to communicate with a reinfusion lumenextending axially through a separate reinfusion catheter which may bepositioned within a reinfusion site in the patient, or with a reinfusionlumen on the access catheter which terminates at an infusion exit port.The exit port may be an end port, or a side port on the first catheter,spaced apart proximally from the distal end of the catheter.

During blood aspiration in the absence of thrombus, the second, low flowmode may aspirate fluid at a rate of no more than about 20 cc/second,generally no more than about 10 cc/second, and typically within therange of from about 1-5 cc/second. The third, high flow mode aspiratesfluid at a rate of at least about 10 cc/second, generally at least about15 cc/second and in one execution of the invention approximately 20cc/second. Generally, the high flow mode aspiration rate will be no morethan about 40 cc/second in an unobstructed aspiration. The low flow rateis typically within the range of from about 10% to about 75%, in someimplementations between about 20% and 30% of the high flow modeaspiration rate.

A second vacuum aspiration system may be provided, via a Y connector inthe tubing (not a separate second pump and cannister) for cooperationwith the first vacuum aspiration system as may be desired depending uponthe clinical situation. The second vacuum aspiration system may have allof the features and options described in connection with the firstvacuum aspiration system except that the outside diameter of the secondcatheter on the second vacuum aspiration system is smaller than theinside diameter of the flow path through the first catheter, and thelength of the second catheter is longer than the length of the firstcatheter.

If a clot is unable to be reached or aspirated by the first vacuumaspiration system, the second catheter may be distally advanced throughthe first catheter and distally beyond the distal end of the firstcatheter, enabling an additional opportunity to retrieve the clot.

In one implementation of the invention, the first catheter may be 24French and having a length within the range of from about 80 cm to about110 cm. The complementary second catheter may be 16 French with a lengthwithin the range of from about 110 cm and about 130 cm. Typically, thesecond catheter will have a length that is at least about 10 cm and insome implementations at least about 20 cm longer than the length of thefirst catheter.

In accordance with another aspect of the present invention, there isprovided a vacuum aspiration catheter and control system. The systemcomprises a housing; a fluid flow path extending through the housing; afirst catheter in fluid communication with the flow path and a connectorconfigured to place a source of aspiration in communication with theflow path; and a flow regulator, configured to regulate fluid flowthrough the flow path. At least a first operator actuated control isprovided, configured to toggle the flow regulator between a default, lowflow mode, and a momentary, operator initiated high flow override mode.The system may additionally comprise a second operator actuated on—offcontrol which toggles between an off mode and the low flow mode, Thefirst and second controls may be carried by the housing.

A secondary catheter port may be provided on the housing, incommunication with the first connector to guide a secondary catheterthrough the housing and into and through the first, large diametercatheter. A hemostasis valve may be carried by the housing, incommunication with the secondary catheter port.

The flow path is defined within a tubular side wall having an insidediameter, and any clinically material changes in the inside diameter inthe direction from the first catheter to the clot collection chamber arean increase. At least a portion of the side wall may be opticallytransparent, to provide a viewing window of the contents of the flowpath. In one implementation, the window is located between the flowcontrol regulator and the first catheter, such as between the housingand the first catheter, or incorporated into the housing or firstcatheter.

The system may be placed in combination with a reservoir for receivingthrombus and blood retrieved through the first catheter as has beendiscussed. A filter may be disposed in the reservoir, and materialtrapped by the filter is viewable through a viewing window in a sidewalldefining the reservoir. The sidewall may be releasably connected to thehousing allowing removal of the reservoir and filter from the housing.

The housing may be integrated into a proximal hub of the first catheter.The housing may be provided with additional controls, depending upon thedesired functionality. For example, one or two or more pull wires mayextend axially through the catheter for the purposes of steering thedistal end of the catheter. The proximal ends of the pull wires may beconnected to a steering control, such as a lever, slider switch orrotary control. The pull wires extend distally through the catheter to asteering zone. A single pull wire implementation permits lateraldeflection in a single direction within a single plane. A two wireimplementation may allow lateral deflection in opposite directionswithin the single plane, or deflection in two different planes withoutrotating the catheter or housing.

In accordance with another aspect of the present invention, there isprovided a method of removing a vascular obstruction. The methodcomprises the steps of transvascularly advancing a distal end of anaspiration catheter into proximity with an obstruction, and activating alow flow, detection mode of aspiration through the catheter. If in thedetection mode the actual flow rate drops to substantially below theexpected flow rate, indicating the detection of a clot, the method mayadditionally comprise the step of manipulating a momentary control toactivate a high flow, bolus aspiration mode of operation to moreaggressively draw obstructive material into the distal end of thecatheter. Activating a momentary control step may enlarge a restrictionin a flow path between the thrombus container and a source of vacuum.The operator may thereafter deactivate (e.g., release) the overridecontrol, and the system will default to the second, low flow mode.Alternatively, a spike in negative pressure may be achieved at thedistal end of the catheter using a dual vacuum chamber system, describedin greater detail below.

Blood and thrombus aspirated during the procedure may be directed into acollection chamber and/or through a filter to separate clot from blood.Filtered blood may be directed back into the patient.

Proximal retraction of the thrombus through the first catheter may befacilitated with the use of a second catheter advanced through the firstcatheter.

The method may comprise advancing the distal end of the first or secondcatheter into proximity with a pulmonary embolism, into proximity with adeep vein thrombosis, or into proximity with a peripheral arterial orveinous occlusion.

In accordance with another aspect of the invention, there is provided aflow control for large bore thrombo-emboli aspiration systems. Thecontrol comprises a housing, defining a central cavity, and having apatient port, a manifold port and a filter port. A movable gate isprovided within the housing, having a flow path and configured toselectively place the patient port in communication with the filterport, the patient port in communication with the manifold port. The sameflow control or separate control may also optionally place the manifoldport in communication with the filter port.

The movable gate may comprise a cylindrical body having a first port incommunication with a second port by a flow path through the body. Thefirst port, the second port and a solid side wall may be spaced betweenabout 120 degrees and 180 degrees apart around the circumference of thegate.

There is also provided a system including a catheter and a hemostasisvalve. The catheter comprises an elongate, flexible tubular body, havinga proximal end, a distal end and a central lumen. The hemostasis valvemay be provided in a housing on the proximal end of the catheter. Thehemostasis valve comprises a collapsible tubular sidewall defining avalve lumen in communication with the central lumen of the catheter. Afilament is formed into a loop around the tubular sidewall, the filamenthaving at least a first tail portion extending away from the loop andconnecting to a first lever. A first spring is configured to move thefirst lever in a direction that pulls the first tail portion away fromthe tubular side wall, reducing the diameter of the valve lumen inresponse to reducing the diameter of the loop.

The filament may further comprise a second tail portion extendingbetween the loop and a second lever. The first and second levers may bebiased in a direction that places the first and second tail portionsunder sufficient tension to reduce the diameter of the central lumen andprovide a seal around a secondary device extending through the valve.The first and second levers may additionally be biased to place thefirst and second tail portions under sufficient tension to close thevalve in the absence of a secondary device extending therethrough.

The inside diameter of the tubing maybe be continuously controlled fromthe collapsible valve lumen's original fully opened inside diameter tofully closed, sufficiently to clinically eliminate leakage of blood orother fluid flow through the valve with or without a dilator, guidewire(s), and/or a catheter in the valve lumen. This enables thehemostasis valve to function with no leaking of air or liquid at anystate between fully closed and fully open as needed. More than onedevice may extend side by side through the hemostasis valve (e.g., aguidewire alongside a catheter).

The hemostasis valve may be shipped with a retention feature such as apin or clip to keep the valve open between production and use. Inaddition, in some clinical situations it may be desirable to hold thevalve open for one or more steps such as to reduce friction with adilator as it is being advanced or retracted through the valve. Aretention feature or clip or control on the housing, which may be in theform of a handle, may be provided to permit selective, temporary lockingof the valve open during the procedure as may be desired.

There is also provided an aspiration catheter placement system,comprising a catheter, having an elongate, flexible tubular body with aproximal end, a distal end, a side wall defining a central lumen, and ahandle on the proximal end; and a dilator, advanceable through thecentral lumen. The dilator has an elongate body, cannulated to receive aguidewire, and an axially extending split extending along the entirelength or a partial length of the elongate body, configured to allowpartial or complete removal of the dilator laterally from the guidewire.

The handle may have a first engagement surface, and the dilator may havea proximal hub with a second engagement surface configured to engage thefirst engagement surface to releasably secure the dilator within thecatheter. The handle may also have a clot container and may also have ahemostasis valve.

There is also provided a method of placing a catheter. The methodcomprises advancing a catheter and cannulated dilator over a guidewireto an intravascular site, and removing the dilator while leaving thecatheter and guidewire in place. The removing step comprises pulling thedilator laterally off of the guidewire as the guidewire progressivelypasses through an axially extending split in the side wall of thedilator. The method may additionally comprise the step of unlocking thedilator from the catheter prior to the removing step.

In accordance with a further aspect of the present invention, there isprovided an aspiration system with accelerated response. The systemincludes an aspiration pump in communication with a first aspirationpump chamber. An aspiration catheter may be placed in fluidcommunication with the first chamber by way of an elongate aspirationtube. A second clot collection chamber is in between the aspiration tubeand the catheter, and a valve is between the clot collection chamber andthe aspiration catheter. Upon opening of the valve, resistance to fluidflow between the clot collection chamber and the distal end of thecatheter is less than the resistance to fluid flow between the clotcollection chamber and the aspiration pump chamber.

A proximal handle may be provided on the aspiration catheter, and thesecond chamber may be carried by the handle. The aspiration tube may beat least about 50 inches or at least about 75 inches or 100 inches long.

The valve may be provided with a spring-loaded actuation for momentaryvalve opening (e.g. by pressing a button or trigger) and automaticclosing, or a control such as a switch, lever, or other mechanism thatdoes not automatically close to enable a more sustained open status.

A first control may be provided on the handle for opening the valve. Thevalve may be normally closed and actuation of the control opens thevalve. A second control may be provided for activating the pump.

The second chamber may be configured to capture clot aspirated by thecatheter. At least a portion of the second chamber may be removablycarried by the handle. The second chamber may comprise a filter membranespaced apart from a transparent wall. The aspiration system mayadditionally comprise a filter membrane, spaced apart from a transparentouter chamber wall. The filter and the chamber wall may be tubular.

The aspiration system may further comprise an operator actuated control,configured to toggle a flow regulator between a default low flow mode,and a momentary, operator initiated high flow override mode. Theaspiration system may additionally comprise a hemostasis valve carriedby the handle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a fluid management system in accordancewith the present invention.

FIG. 2 is a schematic view as in FIG. 1, with a clot attached to agrasping catheter which extends through a large diameter catheter.

FIG. 3 is a schematic view as in FIG. 2, with the clot drawn into atransparent viewing tube on the large diameter access catheter.

FIG. 4 is a schematic view as in FIG. 3, with the clot advancing towardsa thrombus collection chamber.

FIG. 5 is a schematic view as in FIG. 4, with the clot deposited in atransparent thrombus collection chamber.

FIG. 6 is a schematic view of a thrombectomy system configured tore-infuse filtered aspirated blood back into a patient.

FIG. 7A is a schematic view of an alternate configuration of the fluidmanagement system.

FIG. 7B is a schematic view of an alternate configuration of the fluidmanagement system.

FIG. 8 is a schematic view of a grasping catheter configured to applysuction to a clot.

FIG. 9 is a schematic view of an alternative aspiration system inaccordance with the present invention, having a first thrombectomycatheter and a second thrombectomy catheter extending therethrough.

FIG. 10A is a schematic view of the hand piece for the firstthrombectomy catheter of FIG. 9.

FIGS. 10B-10E illustrate interface details between a filter assembly anda handpiece.

FIG. 11A is a schematic view of the handpiece for the secondthrombectomy catheter of FIG. 9.

FIG. 11B is a simplified flow diagram of the dual vacuum chamberaspiration system.

FIG. 11C is a qualitative fluid flow rate diagram at the catheter tip,following opening of the momentary vacuum control valve.

FIG. 12 is a schematic flow diagram for a three-way valve.

FIGS. 13A-13C illustrate three flow configurations for a three-wayvalve.

FIGS. 14A-14C illustrate operation of a hemostasis valve.

FIG. 14D illustrates an alternative filament configuration of thehemostasis valve.

FIGS. 15A-15B are schematic layouts of the components of a proximalhandle of an aspiration catheter.

FIGS. 16A and 16B are different implementations of thrombus engagementtools.

FIG. 17A is a side elevational view of one thrombus engagement tool tip.

FIG. 17B is a longitudinal cross-section through the tip of FIG. 17A.

FIG. 18A is a side elevational view of an alternative thrombusengagement tip.

FIG. 18B is a longitudinal cross-section through the tip of FIG. 18A.

FIG. 19A is a side elevational view of a catheter and split dilatorsystem in accordance with the present invention.

FIG. 19B shows the system of FIG. 19A, with the dilator partiallyretracted and peeled away from the guide wire with the guide wireprogressively escaping from the dilator through an axially extendingsplit.

FIG. 19 C shows the dilator fully retracted from the catheter but stillover the guide wire.

FIG. 19D shows the dilator fully removed from the catheter and the guidewire, leaving the catheter and guide wire unmoved from their positionwithin the vasculature.

FIGS. 20A-20C show a proximal handle for a dilator.

FIG. 21 is a side elevational partial cross section of a catheter havinga cannulated guide rail extending therethrough over a guidewire.

FIG. 22 is a cross sectional view through a dual dilator system such asthat shown in FIG. 23.

FIG. 23 is a side elevational cross section of a distal portion of adual dilator system of the present invention.

FIG. 24 is a cross section as in FIG. 23, with a distal tip formed bythe tubular dilator.

FIG. 25 is a side elevational view of a portion of a tubular dilatorhaving a separation line to allow longitudinal splitting of the sidewallduring proximal retraction from the

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, there is illustrated a fluid management system forlarge bore aspiration procedures. The system 10 includes a largediameter first thrombectomy catheter 12, having an elongate tubular body14 extending between the proximal end 16 and a distal end 18. A centrallumen 20 extends between a proximal catheter connector 22 and a distalport 24 on the distal end 18.

In the illustrated embodiment, the catheter 12 is releasably connectableto a flow control module 28 by way of a complementary module connector30. Module connector 30 provides a releasable connection tocomplementary catheter connector 22, and may include an opener (notillustrated) for opening a hemostasis valve in the hub of the large borecatheter (not illustrated).

The flow control module 28 includes a fluid flow path 32 extendingbetween the module connector 30 and the flow control module 28. Thefluid flow path 32 continues to extend between the flow control module28 and a reservoir 34, which contains a filter for thrombus collectionand/or evaluation and a chamber for filtered fluid chamber (notillustrated). In an alternate implementation of the invention, the flowcontrol module 28 is integrally formed within the hub of thrombectomycatheter 12 to which the catheter may be non-removably attached. Inaddition, the flow path between the flow control module 28 and thereservoir 34 may be contained within a continuous integral tubing, ormay be contained within two or more tubing components releasablyconnectable via complementary Luer locks or other connectors.

Flow control module 28 may include a flow regulator for regulating flowthrough the flow path 32. The flow regulator is configured to provide areversible restriction in the flow path, such as by an expandable orcontractible iris, a ball valve or other rotary core valve, leaf valve,a pinch tubing, or others known in the art.

In one implementation, the flow regulator comprises a collapsibleportion of the tubular wall defining the flow path, such as a section ofpolymeric tubing. An actuator positioned adjacent the tubing is movablebetween a first position where it compresses the tubing, therebyrestricting flow to the low flow rate, and a second position where ithas moved away from the tubing, allowing the tubing to resume its fullinside diameter and allow the high flow rate. The actuator may be springbiased or have other default driver in the direction of the first(restricted) position, and only movable into the second position in thepresence of an affirmative mechanical force or electrical signal thatactuates the high flow override. Upon removal of the momentary overridecommand, the actuator automatically resumes the first, position,producing the low flow mode.

The actuator may be driven by a mechanical control such as a lever orrotatable knob, or an electrically driven system such as a solenoid,operated by any of a variety of buttons, levers, triggers, foot pedalsor other switches known in the art, depending upon the desiredfunctionality.

In another implementation, the fluid flow may be selectively directedthrough a low flow regulator such as a small diameter orifice or tube,and a high flow regulator such as a larger diameter orifice or tube. Amechanically actuated or electromechanically actuated valve canmomentarily divert flow from the low flow to the high flow regulator inresponse to actuating a control.

Flow control module 28 thus includes one or more controls, forcontrolling the operation of the system. One control may be provided fortoggling the system between a no flow (off) mode and a low flow mode.The same or a different control may be provided for momentarily togglingthe flow regulator between the low flow mode and a momentary operatorinitiated high flow override mode. Release of the momentary overridecontrol causes the regulator to revert to off or low flow mode.

The low flow mode enables the first catheter 12 to approach and engagethe clot with a relatively low volume of blood aspiration. Once the clotis engaged, the momentary high flow control may be activated to generatea bolus of high flow vacuum to draw the clot into the catheter 12. Highflow may be at least about 10 cc/second, and preferably at least about15 cc/sec but typically no more than about 25 cc/sec. In oneconstruction the high flow rate is about 20 cc/sec, with all of theforegoing flow rates in an unobstructed aspiration of blood. Low flow asused herein is no more than about 50%, no more than about 35% or no morethan about 25% of the high flow rate. Low flow is generally less thanabout 10 cc/sec or 7 cc/sec, and is often in the range of from about 1-5cc/sec.

The flow control module 28 may be provided with a second catheter port40 in communication with central lumen 20 via a hemostasis valve (e.g.,Tuohy Borst valve)(not illustrated) within the module 28. This allowsintroduction of a second aspiration catheter 42 through the accesscatheter 12 and extending to the treatment site. The second catheter 42may be a smaller diameter aspiration catheter, with or without clotagitation or mechanical grasping capabilities, drug delivery catheter, amechanical disrupter or other accessory device that may be useful in theclot retrieval process. In one implementation, the second catheterincluding its hand piece and controls may be identical in materialrespects to the first aspiration catheter except the second catheter issmaller diameter and longer than the first catheter.

If desired, the second catheter 42 may be connected via a proximalconnector 44 to a complementary connector 46 which is in communicationwith the reservoir 34 via aspiration line 48. Alternatively, aspirationline 48 may be connected to a separate aspiration and collection system(not illustrated).

The clot may be removable through the first catheter 12 under vacuumwithout additional assistance. However if desired, the secondary clotgrasping catheter 42 may be introduced to provide additional attachmentand/or mechanical disruption of the clot to facilitate removal. Removalmay be assisted by the application of vacuum to the grasping catheter 42as well as to the first catheter 12 in sequence or simultaneouslydepending upon the desired clinical performance.

Aspiration pump 50 may include a vacuum pump, and may also include avacuum gauge 51, and an optional a pressure adjustment control 53. Thevacuum gauge 51 is in fluid communication with the vacuum pump andindicates the vacuum pressure generated by the pump. The pressureadjustment control 53 allows the user to set to a specific vacuumpressure. Any of a variety of controls may be utilized, includingswitches, buttons, levers, rotatable knobs, and others which will beapparent to those of skill in the art in view of the disclosure herein.Aspiration pump 50 may alternatively be a manually activated pump suchas a syringe.

Reservoir 34 is in fluid communication with the aspiration pump 50 viavacuum line 35 and acts to transfer vacuum from the air filled side ofthe system to the liquid side of the system, and also to collectaspirated blood and debris. Vacuum line 35 may be used as a flowrestriction. Reservoir 34 thus includes a collection canister in fluidcommunication with flow path 32 and collects aspirated debris. Thecollection canister may include a filter that collects clot, which maybe visually observed or accessed through a window to monitor progress ofthe procedure and/or used for pathologic diagnosis. The vacuum chamberand collection canister may be separate components that are in fluidcommunication with each other or merged within a single housing. Theflow direction through the system may also be reversed to allow theblood to flow through the filter while the clot is collected outside(now downstream) of the filter, e.g. between the filter and the outertransparent window or container.

The flow path 32 extends throughout the length of the first catheter 12,through the control module 28 and into the reservoir 34. A transparentwindow 52 may be provided to enable direct visualization of the contentsof the flow path 32. In the illustrated embodiment, the window 52 is inthe form of a transparent section of tubing between the proximal end ofthe access catheter 12 and the flow module 28, and within the sterilefield so that the clinician can directly visualize debris as it exitsthe proximal end of the access catheter 12 and before it reaches thereservoir 34 which may be outside of the sterile field. The actuallength of the transparent tubing is preferably at least about two orfour or 6 cm long and generally less than about 30 or 20 cm long. Insome implementations, the length of the transparent tube is within therange of about 5 cm to about 15 cm. In an alternate implementation, thetransparent window may be carried by the proximal hub of the accesscatheter 12, or may be a proximal portion of the catheter shaft,distally of the hub.

Referring to FIG. 2, the secondary catheter is in the form of a secondaspiration catheter 42 which has been distally advanced through theaccess catheter 12 and through the vasculature into proximity with aclot 60. The clot 60 may be grasped by the second catheter 42 in any ofa variety of ways such as by mechanical attachment or suction, or both.

Referring to FIG. 3, the second catheter 42 has been partiallyproximally retracted, drawing the clot 60 into the first catheter 12such that the clot 60 becomes visible through the window 52. This may befacilitated by applying vacuum through both the grasping catheter 42 andthe access catheter 12.

Continued proximal retraction of the grasping catheter 42 brings aninterface 62 between the grasping catheter 42 and the clot 60 into viewthrough the window 52. This enables the clinician to visually confirmthat a clot has been captured.

Referring to FIG. 4, further proximal retraction of the graspingcatheter 42 allows the clot 60 to be drawn through the flow path 32 inthe direction of the reservoir 34. The clot 60 is there after drawn byvacuum into the collection chamber within reservoir 34, where it may becaptured by a filter and viewed through a transparent sidewall or window37 on the collection chamber.

Another aspect of fluid management during the thrombectomy procedure isillustrated in FIG. 6. In this implementation, an aspiration line 64places the first catheter 12 in communication with a thrombus filter 66.The thrombus filter 66 is further in communication with a pump such as asyringe aspiration pump 50 by way of aspiration line 68. Actuation ofthe pump 50, such as by proximally retracting the plunger, drawsthrombus through the access catheter 12 and into the thrombus filter 66where thrombus and thrombus particles having a size greater than apredetermined threshold will be entrapped. The thrombus filter 66 may beprovided with a transparent window for a visual confirmation, as hasbeen discussed.

Blood drawn into the syringe 50 will therefore be filtered, with thedebris remaining in the thrombus filter 66. Blood in the pump 50 orother reservoir downstream from the filter may be re-infused into thepatient. In the illustrated configuration this may be accomplished byreversing the pump (pushing the plunger) and pushing filtered blood viaa bypass tube 70 which merges with the flow path 32 on the patient sideof the filter 66 and back into the patient. A valve assembly 74 ispreferably provided to direct thrombus containing blood from the patientinto the filter 66 but ensure that only filtered blood can be pumpedthrough bypass 70 and back into communication with the flow path 32 andinto the patient.

In the illustrated implementation, the valve assembly 74 comprises afirst valve 72 in the bypass tube 70 which permits flow of filteredblood in the direction of the patient but blocks the flow of unfilteredblood through the bypass tube 70 in the direction of the pump 50. Thesecond valve 76 is provided to permit flow of unfiltered blood in thedirection of the filter 66 but prevent the flow of blood from the filterback in the direction of the patient. In one execution of the invention,the first valve 72 and second valve 76 are one way flapper valves thatopen or close in response to blood flow direction.

A further configuration of the fluid management system is schematicallyillustrated in FIG. 7A. Aspiration line 64 places the first aspirationcatheter 12 in communication with the thrombus filter 66. The thrombusfilter 66 is in communication with the aspiration pump 50 by way ofaspiration line 68. Aspiration line 68 includes a flow control 76. Flowcontrol 76 includes an off/on control such as a switch 78. Activation ofthe switch 78 to the ‘on’ configuration places the system in a low flowvacuum mode as has been discussed. Activation of a momentary full flowcontrol such as a button 80 changes the system to the high flow mode.

In an alternate configuration illustrated in FIG. 7B, the flow control76 is moved from between the aspiration pump 50 and thrombus filter 66to in between the catheter and the thrombus filter 66. This allows thenegative pressure in the chamber of thrombus filter 66 to reachequilibrium with the canister in the aspiration pump 50 when the valvein flow control 76 is closed. When the valve is subsequently opened, therelatively short distance between the thrombus filter and the patientallows a rapid drop in negative pressure at the distal end of thecatheter as is discussed in greater detail in connection with FIG. 11B.The flow control 76 my additionally be provided with an optional vent toatmosphere, or to no vacuum, or vent to a source of vacuum at a mildervacuum than that experienced in the cannister of the aspiration pump 50.

FIG. 8 illustrates a second, smaller aspiration catheter 42 such as a 16French catheter, configured for the application of suction to facilitategrasping a clot. In a typical configuration, the second catheter 42 willbe extended through a first, larger catheter 12 (not illustrated) as hasbeen discussed. As with any of the second catheters disclosed here in, amechanical agitator 82 may be axially movably positioned within acentral lumen of the grasping catheter 42. See also FIGS. 16A-18B.Additional details of one suitable mechanical agitator 82 are disclosedin U.S. Pat. No. 10,653,434 to Yang, et al., entitled Devices andMethods for Removing Obstructive Material from an Intravascular Site,the entirety of which is hereby expressly incorporated herein byreference. Additional details of the mechanical agitator 82 aredisclosed in U.S. patent application Ser. No. 15/443,874, filed Feb. 27,2017, entitled Telescoping Neurovascular Catheter with EnlargeableDistal Opening, and U.S. patent application Ser. No. 16/398,626, filedApr. 30, 2019, entitled Devices for Removing Obstructive Material froman Intravascular Site, the entireties of which are hereby expresslyincorporated herein by reference.

Referring to FIGS. 9 and 10A, there is illustrated a furtherimplementation of an aspiration system 100. The system includes a firstthrombectomy catheter 102, such as a large bore aspiration catheter, anda second aspiration catheter 104 which is optionally advanceable throughthe first thrombectomy catheter 102 as has been discussed, or used byitself.

Thrombectomy catheter 102 comprises a proximal handle 106 having anelongate flexible tubular catheter body 108 extending distallytherefrom. The proximal end 110 of the tubular body 108 may bepermanently carried by the proximal handle 106 or may be provided with areleasable connector for detachable connection to a complementaryconnector on the handle 106.

In one implementation of the invention, the tubular body 108 or 152 orboth are provided with a flexible neck 109 extending between proximalend 110 and a transition 111. The flexible neck 109 has a greaterflexibility than the adjacent portion of the tubular body 108 distal tothe transition 111. The flexible neck 109 may have a length of at leastabout 2 cm and often at least about 4 cm, but generally no more thanabout 20 cm or 10 cm or less.

The sidewall of the catheter body 108 within flexible neck 109 includesa helical coil 113 having adjacent filars spaced apart to both improveflexibility, and also allow visualization between adjacent windings ofthe coil. At least the flexible neck 109 includes a sidewall window suchas the spaces between adjacent coil windings which may be in the form ofan optically transparent outer tubular layer, such as any of a varietyof optically transparent shrink tubing polymers. This allowsvisualization of clot through the side wall as it passes through theneck 109 before it enters the proximal handle. The transparent window onthe larger catheter 108 also allows visualization of the distal tip ofthe inner catheter 152 as it passes the window. This may be facilitatedby placing a visual marker on the distal end of the inner catheter 152such as a colored annular band.

For example, in an implementation having a 24 French tubular body 108,the smaller tubular body 152 (e.g. 16 French catheter) may be providedwith a visual indicium such as a white tip on the distal end, that canbe visualized through the sidewall window as it passes through theflexible neck 109. The flexible neck 109 may also be provided on thecatheter shaft 152.

The spring coil 113 may extend distally to a point of termination withinabout one or 2 cm of the transition 111, and, and one implementation, atthe transition 111. Distally of the transition, the sidewall of tubularbody 108 may include a tubular braid, importing greater stiffness andhigher push ability than the helical coil 113.

The proximal end of the catheter may be provided with a rotation controlsuch as a rotatable knob 115 which may be rotationally fixed to thecatheter and rotatable with respect to the handle housing. Thisfacilitates relative rotation between the catheter and the housing forany of the large or small bore catheters disclosed herein.

A central lumen extending through the tubular catheter body 108 is incommunication with a flow path extending through the proximal handle 106to a proximal access port 112. The flow path between the tubularcatheter body 108 and the proximal access port 112 is preferably linear,to axially movably receive the second catheter 104 which may or may notbe utilized in a given procedure. To accommodate the absence of secondcatheter 104 and seal the port 112, the proximal handle 106 ispreferably provided with a homeostasis valve 114 such as a Thuohy-Borstvalve.

A manifold switch 116 controls two way or three way a manifold valve(illustrated in FIG. 12) for selectively controlling fluid flow asdiscussed further below. An aspiration control 117 is provided to turnaspiration on and off. Alternatively, manifold switch 116 can beconfigured to turn aspiration one and off.

A filter assembly 120 includes housing 122 with a side wall 124, atleast a portion of which includes a transparent window 126. Window 126permits a viewing of the contents (e.g. aspirated clot) of a filterchamber 128, which contains a filter 130.

The filter assembly 120 is configured to place the filter 130 in theflow path between the tubular catheter body 108 and the aspirationtubing 118. Preferably the filter chamber can be closed to maintainnegative pressure conveyed from a pump via aspiration tubing 118, oropened to permit insertion or removal of the filter 130. In theillustrated implementation, the filter assembly 120 is removablyconnected to the handle 106. A connector 134 such as a first thread onthe housing 122 is releasably engageable with a complementary connector136 such as a complementary thread on the handle 106. A vent (aperture)to atmosphere may be provided in communication with the filter chamber,to reduce foaming of blood in response to reduced pressure.

The present implementation of the invention includes an integrated flowcontrol module in the proximal handle 106. Thus, an adjustable flowregulator (not illustrated) may be positioned in the flow path, toenable controllable toggling of the aspiration between a low flow modeand a high flow mode. In the illustrated implementation, optional flowregulator is positioned downstream of the filter 130, and containedwithin the housing 122 of the filter assembly 120. A flow regulatorcontrol 132 is provided, to control the flow rate. Preferably, as hasbeen discussed, the flow regulator is configured to regulate fluid flowthrough the flow path at a default low flow rate. Activation of the flowcontrol 132 adjust the flow to the high flow rate mode. Flow control 132may be a momentary button, slider switch, trigger, knob or otherstructure that is preferably defaulted to the low flow mode.

In any of the catheters disclosed herein, carrying the filter chamber128 on the catheter or at least spaced apart from the remote vacuum pumpand vacuum cannister provides enhanced aspiration performance. Thelocation of a conventional aspiration pump may be far enough away fromthe patient to require a length of aspiration tubing between the pumpand the catheter to be as much as 50 inches or 100 inches or more. Thepump typically includes an aspiration canister for blood collection.When aspiration is desired, a valve is opened to place the low pressurecannister in communication with the catheter by way of the aspirationtubing, to aspirate material from the patient. But the length of theaspiration tubing operates as a flow restrictor, causing a delay betweenthe time of activating the vacuum button and actual application ofsuction to the clot.

In accordance with the present invention, the catheter handle 106 or 140contains a filter chamber 128 for example, which is in communicationwith the vacuum cannister on the pump by way of elongate aspirationtubing 118. The momentary aspiration control 117 is in between thefilter chamber 128 and the catheter, which, in the default off position,allows the entire length of the aspiration tubing 118 and the filterchamber 128 to reach the same low pressure as the aspiration cannisteron the pump. The flow restriction between the pump cannister 129 and thefilter chamber 128 is greater than the flow restriction between thefilter chamber 128 and the patient.

In an alternate configurations, 117 may be a vent to atmosphere whichallows the clot canister to be evacuated. Element 142 can alternativelybe an injection port such as for injecting contrast media, saline, ordrugs.

Thus, the only remaining flow restrictor between a source of vacuum(filter chamber 128) and the patient is the relatively short aspirationpathway between the valve in the handpiece and the distal end of thecatheter. When the momentary aspiration control 117 is activated, theflow restriction and enclosed volume on the patient side of the filterchamber is low relative to the flow restriction and enclosed volumethrough aspiration tubing 118 on the pump side of the filter chamber128.

This dual chamber configuration produces a rapid spike in negativepressure experienced at the distal end of the catheter upon activationof the aspiration control 117. The response time between activating theaspiration control 117 and realizing suction actually experienced at theclot is significantly faster and allows significantly higher initialflow than the response time realized in a conventional system havingonly a vacuum chamber located at the pump.

The spike of negative pressure experienced at the distal end of thecatheter will fade as pressure equilibrium is reached between the filterchamber and canister. When the momentary aspiration control 117 isclosed, the vacuum pump will gradually bring the pressure in the filterchamber 128 back down to the level in the vacuum cannister at the pump.

A simplified fluid flow diagram is illustrated in FIG. 11B, and aqualitative flow rate diagram is illustrated in FIG. 11C. The flowrestriction between chamber 128 and the distal and 107 of catheter 108is small relative to the flow restriction between the vacuum canister129 and the vacuum chamber 128. This allows a negative pressure peakexperienced at distal end 107 almost instantaneously upon activation ofvacuum switch 117. The flow rate of material into the catheter 108rapidly reaches a peak and subsides as vacuum chamber 128 fills withaspirated material. The vacuum in chamber 128 declines to a minimum, andslowly recharges by the large vacuum chamber 129 and associated pumpthrough tubing 118. In use, a clinician may choose to allow themomentary vacuum switch 117 to close at or shortly following the maximumflow rate, just giving a short burst or spike of vacuum to facilitatespiration of thrombus into the catheter 108.

Additional details of the filter assembly and related structures areillustrated in FIGS. 10B to 10E. Referring to FIG. 10B, the filterassembly 120 includes a tubular sidewall 124 having a transparent window126. In some implementations the entire tubular sidewall 124 can be atransparent window. The side wall 124 encloses a filter 130 as has beendiscussed. The filter 130 includes a tubular filter sidewall 320defining an interior chamber 321 for filtered blood. Filtered blood isdrawn in the direction of vacuum line 210 through a first vacuumaperture 322 and into a flow path 324 having a vertical offset 326 inthe flow path 324. The vertical offset 326 allows removal of blood fromthe bottom of the chamber, through a flow path and out through a secondvacuum aperture more centralized with respect to a central axis of thetubular sidewall 124 and in communication with vacuum line 210.

The filter 130 is displaced downward with respect to a centrallongitudinal axis of the tubular sidewall 124, leaving the filterchamber 128 having a chamber height 129 at least as great as the insidediameter of a filter line aperture 330 leading to filter line 208. Thisallows clot to move from filter line 208 into the filter chamber 128without restriction, and optimizes the volume of filter chamber 128 ontop of the filter 130 for viewing through the window 126.

A connector 134 maybe carried by the filter assembly 120, such as in theform of a bayonet mount, or other releasable attachment to the handpiecehousing. A first seal 332 such as an annular elastomeric ring may beprovided between the tubular sidewall 124 and the complementary surfaceon the handpiece housing.

A second vacuum aperture 328 is in communication with the first vacuumaperture 322 by way of the flow path 324. Second vacuum aperture 328 maybe carried on an axially extending tubular projection 336 which may beremovably received within a complementary recess on the hand piecehousing.

A second seal 340 such as an elastomeric ring maybe provided surroundingthe flow path 324, for providing a seal between the filter assembly andthe handpiece. In the illustrated implementation, the second seal 340surrounds the tubular projection 336 and is configured to seal againstan adjacent complementary surface on the handpiece in the as mountedorientation.

Referring to FIG. 10D, the filter assembly 120 additionally includes afilter base 342 through which filter line aperture 330 extends. The flowpath 324 additionally extends through the filter base 342, and, in theillustrated implementation, exits the tubular projection 336 carryingthe second vacuum aperture 328.

A complementary docking platform 350 is carried by the handpiece, havingcomplementary connector to connector 134 for rapid attachment anddetachment of the filter assembly 120 from the handpiece. In theillustrated embodiment, at least a first flange 352 maty be receivedthrough an opening 354 on the filter assembly 120. Rotation of thefilter assembly 120 moves the first flange into interference fit with asecond flange 356 to secure the filter assembly 120 to the dockingplatform 350 on the handpiece. Two or three or four or more similarflange and complementary opening pairs may be provided around theperiphery of the components. In the illustrated implementation, thecircumferential arc length of the flange and corresponding opening onone of the three pairs is greater than the other two pairs to functionas a key, so that the filter assembly can only be secured to the dockingplatform in a single rotational orientation.

The docking platform 350 includes a filter line aperture 360 forcommunicating with filter line 208, and a vacuum line aperture 362 forplacing the filter 130 in communication with a source of vacuum. Thedocking platform 350 may be connected to a two way valve 362 or a threeway valve as is discussed elsewhere herein depending upon the desiredfunctionality. The valve may carry a rotatable drive gear 304 to rotatethe interior rotatable valve gate as is discussed in additional detailbelow. Alternatively, a lever or other control on the housing may beconfigured to rotate a shaft directly coupled to the rotatable part ofthe valve.

A valved flow path may also be provided for venting the filter chamber128 directly to atmosphere. The valve may be opened such as bydepressing a momentary button, which is biased in the closed direction.This can create an abrupt change in pressure at the distal end of thecatheter, which may facilitate clot aspiration. This can also be used todischarge vacuum

Referring to FIG. 11A, additional details of the handle 140 of thesecond catheter 104 are disclosed. The handle 140 extends between aproximal end and a distal end. An elongate flexible tubular body 152extends distally from the distal end of the handle 140 and is configuredto advance distally through the proximal handle 106 and the tubular body108 of thrombectomy catheter 102.

A steering dial 144 may be provided to place one or more steering wiresunder tension, to deflect a deflection zone near the distal end of thetubular body 152. A manifold switch 116 may be provided to control theflow of fluid as will be discussed below. The handle additionallycomprises an aspiration control 117 such as a slider switch, for turningaspiration on or off. A max button 132 may be provided for delivering amomentary pulse of high aspiration rate as has been discussed.

Fluid flow through the thrombectomy system is controlled by manifoldswitch 116 (see, e.g., FIG. 9), which may control a two way or three-wayvalve. Referring to FIG. 12, a schematic flow diagram for three-wayvalve 200 is provided. Patient line 202 can be placed in fluidcommunication with the patient, via a catheter such as a large diameterthrombectomy catheter 12 or second catheter 42.

Patient line 202 may be placed in communication with a manifold line 204by advancing the three-way valve 200 to a first position, such as toallow delivery of medications, contrast media or saline to the patient.

Adjustment of the three-way valve 200 to a second position can isolatepatient line 202 and place the manifold in communication with the filter206 via filter line 208. Activation of a vacuum pump will draw bloodfrom the patient and through the filter 206 via vacuum line 210.

Further adjustment of the three-way valve 200 to a third position willplace the manifold in communication with the vacuum line 210, such as topermit a saline flush of the filter 206. This third position may beeliminated depending upon the desired functionality.

One implementation of a suitable three-way valve 200 is illustrated inFIGS. 13A through 13C. Referring to FIG. 13A, the valve 200 may comprisea housing 220 such as a cylindrical housing having a central cavity 221.A rotatable cylindrical gate 222 may be positioned in the central cavity221, as illustrated in the exploded view of FIG. 13A. Rotatable gate 222is provided with a flow path 224 extending between a first end 226 and asecond end 228. In the illustrated implementation, the first end 226 anda second end 228 of the flow path are spaced apart around thecircumference of the rotatable gate by approximately 120 degrees.

In the rotational orientation of the rotatable gate 222 illustrated inFIG. 13A, the first end 226 of the flow path 224 is in communicationwith a first port 232, and the second end 228 of the flow path 224 is incommunication with a second port 234. This corresponds to the firstposition discussed previously, in which the patient is in fluidcommunication with the manifold.

FIG. 13B illustrates rotatable gate 222 in the second position where theflow path 224 places the first port 232 in communication with the thirdport 230 to place the filter 206 in communication with the manifold. Therotatable gate 222 may be toleranced within the cavity 221 such that therotatable gate 222 seals the second port 234 thus isolating the patientfrom the flow path in this orientation. Similarly, in each of the othertwo orientations, two of the ports are placed in communication with theflow path, while the third port is isolated from the flow path.

The third position is illustrated in FIG. 13C, in which the flow pathplaces the second port 234 in communication with the third port 230,placing the filter 206 in communication with the patient, and isolatingthe manifold from the flow circuit.

The foregoing selectivity may be achieved by spacing the three portsapproximately 120 degrees apart around the circumference of the housing,to cooperate with the flow channel 224 end ports which are about 120degrees apart around the circumference of the cylindrical gate 222. Thegate 222 may be rotated within the housing 220 by a connector 236extending through the housing 220 such as along the axis of rotation,and connected to a control 116 such as a rotatable knob, lever or sliderswitch with a rack and pinion drive assembly.

Each of the catheters disclose herein may be provided with a hemostasisvalve on the proximal end, to allow selective closing of the centrallumen to completely closed without any devices extending therethrough,from a sealed fit around devices of differing diameters such as a guidewire or a secondary catheter extending therethrough. One example of asuitable hemostasis valve is schematically illustrated in FIGS. 14Athrough 14C.

Referring to FIG. 14A, hemostasis valve 250 includes a frame 252 forsupporting a flow path defined within a tubular sidewall 254. The frame252 may be integrally formed with or mounted to the catheter handle orhub.

The flow path and tubular sidewall 254 extend between a first end 256and a second end 258. First end 256 may be a port 112 (see, e.g., FIG.9) on the proximal end of any of the catheters disclosed herein. Secondend 258 may be in communication with the central lumen of thecorresponding aspiration catheter, such that devices entering the firstend 256 and advanced axially through the flow path can advance all theway to the distal end of the aspiration catheter and beyond.

At least a portion 260 of the sidewall 254 is collapsible in response toexternal pressure. That portion 260 and optionally the full length ofthe tubular sidewall within valve 250 may be comprise a collapsibleelastic tube such as silicone tubing, which is biased into an open lumentubular configuration when unconstrained. A compression element such asfilament 262 is configured to apply compressive force against thesidewall 254 to reduce the inside diameter of the flow path to provide aseal against itself (when completely closed with no devices extendingtherethrough) or against a device such as a guidewire or catheterextending therethrough. In the illustrated implementation, the filament262 forms a loop 268 around the collapsible portion 260 of tubularsidewall 254. Retraction of a first tail portion 270 of the filament 262away from the sidewall 254 constricts the diameter of the loop 268thereby collapsing the portion 260 of the tubular sidewall asillustrated in FIG. 14 A.

In the illustrated implementation, the first tail portion 270 of thefilament 262 may be retracted by at least a first lever 264. Lever 264may be connected to the frame 252 by a first pivot 266 and is attachedto the tail portion 270 at an attachment point 272. Advance of the leverin a first direction places the filament under tension and reduces theinside diameter of the valve. Releasing the lever removes the tensionand the collapsible portion 260 of the sidewall rebounds to itsunconstrained, open lumen configuration.

In the illustrated implementation, a second lever 274 is attached to theframe 252 at a second pivot 276, and is attached to a second tailportion 278 of the filament 262. Each of the first and second tailportions may comprise a single filament or two or three or more parallelfilaments. In the two filament configuration as illustrated, thefilaments may be immovably secured to the lever, or may be a continuousfilament, looped around a fulcrum 280. The loop 268 may comprise one ortwo or three or more revolutions around the tubular sidewall, dependingupon the desired performance.

At least one lever 264 is provided with a spring 282 to bias the leveraway from the tubular sidewall, constricting the inside diameter of thecollapsible portion 260 into sealing engagement with a device extendingtherethrough, or to a completely closed configuration in the absence ofa device. As illustrated, a second lever 274 may also be biased usingthe same spring or a second spring.

As illustrated in FIG. 14C, compression of the levers in a medialdirection towards the axis of the tubular sidewall 254 releases tensionon the tail portions of the filament and allows the valve to open, suchas to permit advance of a catheter through the valve. Releasing thelevers allows the spring bias to retract the tail portions, reducing thediameter of the loop 268 and collapsing the collapsible portion 260 intosealing engagement with the outside surface of the secondary catheter,at an intermediate valve diameter as seen in FIG. 14B.

Retraction of the tail portion 270 of filament 262 may alternatively beaccomplished by winding the tail portion 270 around a rotatable spoolsuch as a shaft or drum. Rotation of a knob or advance of a lever causesthe spool to take up filament and collapse the sidewall.

An alternate configuration for the filament 262 is illustrated in FIG.14 D. In this implementation, the first tail portion 270 slidablyextends around a first fulcrum at 272 and returns to attach to thehousing at an attachment point 271. First tail portion 270 extends fromthe fulcrum to form a loop 268 around the collapsible tube. The filament262 may make a single revolution or two or more revolutions around thecollapsible tube before continuing on around a second fulcrum at 280, toa second point of attachment 279 to the housing.

Compression of the first lever 264 and second lever 274 loosens the loop268, allowing the lumen to resume patency. Releasing the levers allowsthe spring bias to reduce the diameter of the loop 268 as the first tailportion 270 and second tail portion 278 slide away from each otheraround the left and right fulcrums. Preferably, friction between thefilament 262 and fulcrums are minimized, as by providing a lubriciousoil such as silicone oil around the fulcrums at 280 and 272, as well asusing Teflon braided line for the filament 262.

Various components of the aspiration system handle are schematicallyrepresented in context in FIG. 15A. The proximal handle 140 on a secondcatheter 104 includes a filter 206, a tubular body 152 and otherfeatures previously described. Two-way or three-way valve 200selectively controls flow among the filter line 208, patient line 202and manifold line 204. In this implementation, the three-way valvecontrol 116 is in the form of the slider switch. The slider switchaxially movably displaces a first linear rack gear 300. Rack gear 300engages a pinion gear 302, which may either directly rotate the gate inthe valve 200, or, as illustrated, drive a third gear 304 which rotatesthe rotatable gate within 200. An alternative valve control system isschematically illustrated in FIG. 15 B. In this implementation, theslider switch, linear rack gear 300 and pinion gear 302 omitted. A valvecontrol 116 in the form of a lever 117 is attached directly to a shaftwhich controls rotation of the valve gate. The lever may be advancedproximally or distally, to adjust the flow path through the valve as hasbeen discussed.

A steering mechanism 306 is provided to permit steering of the secondcatheter 152. Manually rotatable knob 148 allows manual rotation of acore wire and distal helical tip as has been discussed. The core wireaxially movably extends across hemostasis valve 146. Alternatively, thecore wire and tip (e.g., thrombus engagement tool 400) may be coupled toa motorized drive unit at the proximal end of the catheter system.

In certain implementations of the invention, an aspiration catheter suchas a 16 French catheter is advanced transvascularly over a wire and/orthrough a larger diameter (e.g., 24 French aspiration catheter) to thetreatment site. If the application of vacuum is not able to aspirate theclot into the 16 French catheter, an elongate flexible thrombusengagement tool may be advanced through the 16 French aspirationcatheter, to facilitate retrieval of the clot.

Referring to FIGS. 16A and 16B, the thrombus engagement tool 400 maycomprise an elongate flexible shaft 402 having a proximal end 404 and adistal end 406. A proximal hand piece such as a handle 408 may beconfigured to be rotated by hand. Distal end 406 carries a clotengagement tip 410 which may include one or more radially outwardlyextending structures such as a helical thread 412. The handle 408 mayhave an indicium of rotational direction such as a printed or moldedarrow 109 which indicates the direction to rotate the handle 408 inorder for the helical thread 412 to engage clot.

In one implementation illustrated in FIG. 16B, the thrombus engagementtool 400 carries a clot engagement tip 410 of the type illustrated inFIGS. 18A and 18B. The proximal end of the tip 410 is glued to thedistal end of a braid-reinforced polyimide tube. The proximal end of theMicrolumen has a cannulated torquing handle 408, and the whole assemblyis cannulated so it can be delivered and function over a wire 468 suchas an 0.035″ wire. The 0.035″ wire helps maintain space between the tipand the vessel wall, and the wire can be pulled back inside the workinglength of the flexible shaft 402 during rotation and engagement with theclot as needed.

Referring to FIG. 17A, the distal tip 410 includes a helical thread 412extending from a distal end 414 to a proximal end 416 and supported byflexible shaft 402. The axial length of the distal tip 410 is at leastabout 2 mm or 5 mm or 10 mm and in some embodiments no more than about30 mm or 20 mm measured along the flexible shaft 402. The helical thread412 wraps around the axis at least about 1 or 2 or 4 or more fullrevolutions, but in some embodiments no more than about 10 or 6revolutions. In some embodiments the axial length along the threadedportion of the tip is within the range of from about 1 to about 8revolutions.

The helical thread 412 on this implementation may have a constant pitchthroughout its length. The pitch may be within the range of from about10 to about 20 threads per inch, or about 5 to about 10 threads per inchdepending upon desired performance. Alternatively, the thread may havemultiple pitches designed to engage, transport and grasp thrombus withinthe catheter lumen. A distal pitch may be less than a proximal pitch.The pitch may vary continuously along the length of the thread, or maystep from a first, constant pitch in a proximal zone to a second,different pitch in a distal zone of the thread. The thread 412 maycomprise a continuous single helical flange, or may have a plurality ofdiscontinuities to produce a plurality of teeth or serrations, arrangedhelically around the core wire.

The side elevational profile or envelope scribed by the distal tip as itrotates may have a linear or nonlinear taper on one or both ends (e.g.,football shaped) which provide varying diameter and thus clearance alongits length from the generally cylindrical ID of the catheter lumen.

The maximum OD of the thread 412 is preferably smaller than the diameterof a sliding fit within the catheter lumen, and may generally be atleast about 0.015 inches or 0.010 inches smaller than the catheter lumenID. In some implementations, the Max OD of the tip may be significantlyless than the inside diameter of the catheter lumen to allow more spacefor the thrombus, but still create significant grasping force viaengagement of the helical threads with the thrombus. In oneimplementation, the maximum helical thread diameter is about 0.110inches and the catheter lumen ID is about 0.275 inches (24 F) (a 0.165inch gap between the helical threads and catheter wall.

In certain applications, the Max OD of the tip is no more than about 35%or no more than about 40% or no more than about 60% of the ID of thecatheter, to leave a substantial tip bypass flow path. Since thisimplementation does not have any centering structures for the tip 410 orshaft 402, the tip will normally be pushed to one side of the aspirationlumen. When a clot becomes lodged between the tip and the opposing wallof the catheter, manual rotation of the tip can engage the clot like aworm gear and either grasp the clot (e.g., by pinning it against theopposing catheter sidewall) for retraction or facilitate freeing theblockage and aid in ingestion of the clot into the catheter.

The profile of the tip 410 viewed along the axis of rotation may becircular, or may vary to create a non circular pattern around the axisof rotation. The tip as seen in an end elevational view thus exhibits amajor diameter and a minor diameter. The minor diameter may be no morethan about 95% or 90% or 80% or 70% of the major diameter, dependingupon desired performance.

Referring to FIGS. 17A and 17B, the illustrated tip 410 includes adistal advance segment 418 extending between an atraumatic distal tip at420 and a transition to the distal end 416 of the thread 412. Helicalthread 412 extends proximally from the transition to a proximal end 414of the helical thread 412. A trailing segment 422 extends between theproximal end 414 of the thread and the proximal end 424 of the tip.

The axial length of the advance segment 418 may be at least about 1 cmor 2 cm and in some implementations is within the range of from about 2cm to about 4 cm. The axial length of the helical thread 412 along thelongitudinal axis is typically within the range of from about 1 cm toabout 5 cm and in certain implementations between about 2 cm and 3 cm.

The outside diameter of the advance segment 418 at distal tip 420 isgenerally less than about 0.024 inches, or less than about 0.020 inchesand, in one implementation, is about 0.018 inches. The maximum outsidediameter of the advance segment 418 and helical thread 412 may be withinthe range from about 0.020 to about 0.045 inches, and, in oneimplementation, is less than about 0.040 inches, such as about 0.035inches. The advance segment, helical thread and trailing segment of thetip 410 may be molded over the flexible shaft 402 using any of a varietyof polymers known in the catheter arts.

Referring to FIG. 17B, a first radiopaque marker 430 may be carried onthe flexible shaft 402 beneath the advance segment 418. A secondradiopaque marker 432 may be carried on the flexible shaft 402 withinthe trailing segment 422. Each radiopaque marker may comprise aradiopaque tube or a coil of radiopaque wire such as a platinum iridiumalloy wire having a diameter about 0.002 inches, and wrapped around theflexible shaft 402 and soldered to the flexible shaft 402 to produce anRO coil having an outside coil diameter of less than about 0.020 inches,such as about 0.012 inches. The radiopaque markers may also function asan axial interference fit between the flexible shaft 402 and the moldedadvance segment 418 and trailing segment 422 to resist core wire pullout from the tip 410.

In one implementation, the maximum OD of the thread 412 exceeds themaximum OD of the advance segment 418 by at least about 15% or 25% or30% or more of the OD of the advance segment 418, to facilitate crossingthe clot with the advance segment 418 and engaging the clot with thethread 412. The thread pitch may be within the range of from about 0.75to about 0.30, or within the range of from about 0.10 and about 0.20,such as about 0.14 inches.

Preferably, the maximum OD of the tip 410 is less than about 60% or lessthan about 40% of the aspiration catheter ID at the distal end of thecatheter, and may be within the range of from about 35% to about 55% ofthe catheter ID. In certain implementations, the maximum OD of the tip410 may be within the range of from about 0.044 inches to about 0.041inches within a catheter having a distal end ID within the range fromabout 0.068 inches to about 0.073 inches.

Depending upon the clinical application, it may be desirable to controlthe extent to which, if any, the distal tip 410 can extend beyond thedistal end of the catheter. For example, distal extension of the distalend of the helical tip beyond the distal end of the catheter may belimited in some implementations to no more than about 5 mm or 3 mm or1.5 mm or 1.0 mm or less. In other clinical environments the distal tip420 may be permitted to extend at least about 2 cm or 3 cm andpreferably as much as 4 to 8 cm beyond the catheter, but generally willbe limited to extend no more than a preset distance such as 12 cm or 8cm or 5 cm beyond the catheter depending upon desired performance. Inone implementation, distal advance of the tip 410 is limited so that thedistal end is within 2 cm or within 1 cm or no more than 0.5 cm ineither the distal or proximal direction from the distal end of theaspiration catheter.

Distal advance of the tip 420 may be limited by providing mechanicalinterference at the desired distal limit of travel. In oneimplementation, a distal stop surface 440 on the handle 408 provides aninterference engagement with a complementary proximal surface carried bythe aspiration catheter through which the thrombus engagement tool 400is advanced. Alternatively, a distal engagement surface can be carriedanywhere along the length of the thrombus engagement tool 400, forsliding engagement with a complementary proximally facing stop surfacecarried by the catheter. Additional details may be found in U.S. patentapplication Ser. No. 17/036,258 filed Sep. 29, 2020 and entitled EmbolicRetrieval Catheter, which is hereby expressly incorporated in itsentirety herein by reference.

The limit on distal advance of the helical tip may include a firstconfiguration in which distal advance is limited to a first positionproximate the distal end of the evacuation catheter to prevent injury tothe vascular wall. Upon a user initiated adjustment, the helical tip maybe advanced to a second position farther out of the distal end of thecatheter such as for inspection and cleaning purposes. This adjustmentof the limiting mechanism may be locked out following cleaning orinspection, to limit distal travel to the first position to prevent anundesired degree of exposure of the helical tip element when the systemis within the patient's vasculature. Any of a variety of movableinterference levers of pins may be engaged to limit travel to the firstposition, or disengaged to allow travel to the second position.

Referring to FIGS. 18A and 18B, a tip 410 includes a tubular sidewall440 defining a hub having a connector such as a cavity 442 for coaxiallyreceiving the distal end of a support shaft such as a braid reinforcedpolyamide tube. The inside diameter of the cavity 442 steps down at adistal end of the hub at a step 444 to a smaller diameter lumen 446 incommunication with a distal opening 448. This provides a continuouslumen throughout the length of the micro lumen shaft and tip 410 so thatthe thrombus engagement tool can be introduced over the wire.

In general, the pitch of thread 412 may be within the range of fromabout 0.07 to about 0.11, and in one embodiment, is about 0.09. Thewidth of the thread 412 measured along an axis that is perpendicular toa face of the thread may be within the range of from about 0.009 toabout 0.04, and, in one embodiment, is about 0.02. The greatest majordiameter of the thread 412 may be at least about 10%, or at least about15%, or at least about 20% greater than the diameter of the proximal hubend of the tip 410 surrounding the cavity 442. In one implementation,the outside diameter of the proximal hub is about 0.090 inches and theoutside diameter of the thread 412 is about 0.110 inches. The actuallength of the tip 410 including the proximal hub may be within the rangeof from about 0.2 inches to about 0.8 inches and in some implementationswithin the range of from about 0.4 inches to about 0.6 inches.

The tip 410 may be manufactured in accordance with any of a variety oftechniques known in the art, such as machining, etching, additive and/orsubtractive processes. In one implementation, the tip 410 is molded froma polymer such as PEBAX, which may be a 55 D hardness. The PEBAX mayinclude a radiopaque agent, such as bismuth sub carbonate, present inthe range of from about 50% to about 70% by weight.

Any of the tip dimensions and configurations disclosed herein may bere-combined with any of the other tip dimensions, configurations, driveshafts and associated structures depending upon the desired clinicalperformance.

Referring to FIGS. 19A-19D, there is illustrated a split dilator system450 which may be utilized with any of the catheters disclosed herein.The system includes a catheter 452 having an elongated tubular body 454extending between a proximal end 456 and a distal end 458. Proximal end456 is provided with a proximal hub or manifold 457 as has beendiscussed in connection with other catheters disclosed herein.

An elongate flexible dilator 460 has a length sufficient to extendthroughout the entire length of the catheter 452. Dilator 460 extendsbetween a proximal end 462 and a distal end 464 having a tapered distaltip 466. The dilator 460 is provided with a central lumen (notillustrated) so that it may be advanced over a guide wire 468. Proximalend 462 of the dilator is provided with a proximal hub 470.

A split 472 extends the length of the hub 470 and along the sidewall ofthe tubular dilator 460. The split may be in the form of a slotextending through the entire wall thickness of the dilator, aperforation line, a groove, or other weakening to allow the formation ofa slit through the dilator side wall, and through which the guide wire468 may be laterally removed as discussed further below. Thelongitudinal split 472 may extend the entire length of the dilator 460,or extend from the proximal end in a distal direction to an endpoint 473within the range of from at least about 2 cm or 5 cm to no more thanabout 40 cm or 30 cm from the tapered tip 466.

Preferably, a first locking component carried by the hub 470 isreleasably engageable with a complementary second locking componentcarried by the hub 457.

Referring to FIG. 19 B, following trans vascular advance of the catheterand dilator assembly to the desired intravascular location, the dilator460 may be proximally removed leaving the catheter 452 in place.Desirably, the guide wire 468 may remain unmoved in position at thetarget vascular site while removing the dilator 460, preferably withoutthe need for a proximal guide wire extension. For this purpose, theguide wire 460 may be laterally progressively removed from the dilatorat a parting point 473 that advances axially along the split 472, as thedilator 460 is proximally retracted from the catheter 452 and guidewire468.

Once the tapered tip 466 has been proximally retracted from thecatheter, the guide wire 468 may be grasped between the dilator 460 andthe catheter 462, and the dilator 460 may be proximally removed from thecatheter 452 and from the guide wire 468. This allows removal of thedilator without disturbing the position of the catheter or the guidewire, which are thereafter available for a subsequent intravascularprocedure.

Referring to FIGS. 20A and 20 B, there is illustrated a proximal dilatorhandle 480. The handle 480 comprises a body 482 having a proximal end484 a distal end 486 and a longitudinal axis. At least a first proximalgripping surface 488 is carried by the body. In the illustratedimplementation, a first gripping surface 488 is provided on at least oneside of a paddle shaped grip 490, configured to be held between a thumband forefinger. A second gripping surface 492 may be provided on anopposing side of the handle. Gripping surfaces may be provided with afriction enhancing surface structures such as a plurality of ridgesoriented transverse to the longitudinal axis of the dilator handle 480.

A proximal exit port 494 in communication with the dilator guidewirelumen is oriented along the longitudinal axis of the dilator handle 480,such that a guide wire extending out of the exit port 494 lies along thefirst gripping surface 488. This allows a clinician to pin the guidewire to the gripping surface 488 using a finger such as a thumb, therebyenabling the dilator and the guide wire to be moved as a unit using onehand.

The dilator may be removably secured to the catheter such as by aretention clip 496 carried by the proximal end of the handle. A releasesuch as a button or deformable interference snap fit may be provided tounlock the dilator handle from the housing, enabling the dilator to beproximally withdrawn from the catheter. In the illustratedimplementation, a retention surface such as a proximal surface of aretention ring 497 carried by proximal end 486 of the body 482 providesan interference fit with the retention clip 496. This combines thedilator and handle/catheter into a single system. The paddle may bereleased from the retention clip by depressing at least a first button506 and as illustrated also a second button 508 carried on the upper andlower sides of the retention clip housing, and proximally withdrawingthe paddle.

This is the same connection and release dock for use with a thrombusengagement tool such as engagement tool 400 discussed in connection withFIGS. 16A and 16B. A distal limit safety feature on the thrombusengagement tool 400 fits into the retention clip 496, ensuring that thedistal tip of the tool 400 can not be advanced forward beyond the distaltip of the catheter without both aligning a projection on the tool 400with the rotational key 502 and intentionally advancing the tool 400through the retention clip while depressing at least the first button506 or other unlock control.

Once the distal limit has been released, the tip 410 may be distallyadvanced no more than about 4 cm and generally about 1 cm to 2 cm beyondthe distal end of the catheter. This is intended to be accomplished oncethe thrombus engagement tool has been withdrawn from the patient, toallow visual inspection of the tip 410.

The engagement tool 400 may also be proximally retracted within thecatheter, typically for less than about 3 cm or less than about 2 cm,and may be provided with a spring bias to return to approximate axialalignment between the distal end of the tip 410 and the distal end ofthe catheter.

A hemostasis clamp 500 may be provided, to hold the hemostasis valveopen such as during shipping, or during the advance or withdrawal ofdevices therethrough. The hemostasis valve is opened by depressing atleast a first control button, and in the illustrated implementationfirst and second control buttons positioned on opposing sides of thehandle. The hemostasis clamp comprises a generally U shaped body 502having a first arm 504 configured to depress a first button, and asecond opposing arm (not illustrated) configured to depress a secondbutton on an opposite side of the handle. The hemostasis clamp 500 maybe removably retained on the handle by a friction fit, or aninterference fit between the handle and the body which can be overcomeby plastic deformation as the body is pulled away from the handle torelease the hemostasis control buttons.

Referring to FIG. 21, an elongate flexible cannulated rail or dilator561 is shown extending over the guidewire 570 and occupying the spacebetween the guidewire 570 and the large inside diameter of the centrallumen 558 of the large diameter catheter 560 to provide support to thecatheter and/or an atraumatic tip during delivery.

This catheter-cannulated rail-guidewire assembly is intended to easilytrack through anatomical challenges more easily than the catheter. Thecatheter-rail-guidewire assembly then acts as a first stage of thecatheter delivery system and enables the large diameter catheter orcatheter system to be inserted and independently advanced over thisfirst stage into a blood vessel (e.g. the femoral vein) percutaneouslyover a guidewire and advanced through potentially tortuous vasculatureto the remote target location of interest without requiring advancedskills or causing kinking of the catheter.

The cannulated rail 561 may comprise a soft flexible cylindrical bodyhaving a guidewire lumen with a diameter of no more than about 0.040″and an outside diameter no less than about 0.025″ or about 0.010″smaller than the inner diameter of the large diameter catheter. Thus thewall thickness of the cannulated rail 561 is typically at least about0.010″ less than the radius of the large diameter catheter and in someimplementations at least about 0.120″ or more, depending upon the sizeof the annular space between the inside diameter of the catheter and theoutside diameter of the guidewire.

The cannulated rail 561 may have an elongated tapered distal tip 562that may project beyond the distal end 554 of the catheter 560. Thethick sidewall of the cannulated rail 561 may comprise one or moreflexible polymers, and may have one or more embedded column strengthenhancing features such as axially extending wires, metal or polymericwoven or braided sleeve or a metal tube, depending upon the desiredpushability and tracking performance along the length of the dilator.

Optionally, the proximal segment of the rail or dilator which is notintended to extend out of the distal end of the catheter may be astructure which is not coaxial with the guidewire, but a control wirewhich extends alongside the guidewire in the catheter and allows thedistal tubular telescoping segment of the rail or dilator to beretracted or extended. (analogous to rapid exchange catheters) withoutthe entire length of the rail structure being over the wire. This allowsremoval or insertion of the rail or dilator over a shorter guidewirebecause of the shorter coaxial segment tracking over the guidewire.

Catheter 560 may be provided with a proximal hub 520, having a port foraxially movably receiving the rail 561 therethrough. The hub 520 may beprovided with an engagement structure such as a first connector 522 forreleasably engaging a second complementary connector 524 on a hub 526 onthe proximal end of the rail 561. First connector 522 may comprise aninterference structure such as at least one radially moveable projection530, for releasably engaging a complementary engagement structure suchas a recess 532 (e.g., an annular ridge or groove) on the hub 526.Distal advance of the rail 561 into the catheter 560 causes theprojection 530 to snap fit into the recess 532, axially locking thecatheter 560 and rail 561 together so that they may be manipulated as aunit.

The dilator is inserted through the hemostasis valve in the hub 520 of alarge bore (e.g., 24 F) catheter 560 and advanced through the catheteruntil the retention clip on the dilator hub 526 or catheter hub 520snaps into the complementary recess on the other hub. In this engagedconfiguration, an advance segment along the flexible distal end of the24 F rail dilator 561 will extend at least about 5 cm or 10 cm, and insome implementations at least about 15 cm or 20 cm beyond the distal end554 of the 24 F catheter 560. The rail dilator and 24 F catheter systemare thereafter distally advanced over a previously placed guidewire andinto the introducer sheath.

The dilator and catheter combination of the present inventiondifferentiate over prior systems both because of the flexibility of adistal zone of the dilator and greater length of the dilator than thecorresponding catheter. Typically, a dilator is a uniform stiffness andlength-matched to its catheter, with only a short atraumatic tip of thedilator extending beyond the distal end of the catheter. The dilator ofthe present invention has a supportive proximal end and a flexibledistal end, with a total dilator length much longer than the catheter 60to enable, as an example, the following procedure.

In use, a guidewire 570 such as an 0.035″ guidewire is advanced underfluoroscopy using conventional techniques into a selected vessel. Thecannulated rail 561, optionally with the catheter 560 mounted thereon,is loaded over the proximal end of the guidewire 570 and advanceddistally over the wire until the distal end of the rail is in positionat the target site.

The 24 F catheter 560 is thereafter unlocked from the rail 561 andadvanced over the rail 561 to the desired site, supported by the rail561 and guidewire 570 combination. Because the uncovered advance sectionof the rail has already traversed the challenging tortuosity through theheart, the catheter 561 now just slides over the advance section of therail for easy passage to the final target location. The supportiveproximal zone and flexible distal advance section of the rail enablesease of delivery through the most challenging anatomy in, for example, aPE procedure going from the vena cava through the tricuspid andpulmonary valves of the heart into the central pulmonary artery withoutconcern about damaging the tissue (atraumatic, flexible tip) or damagingthe dilator (high kink resistance due to flexible, high wall thickness“solid” dilator construction.

The cannulated rail 561, or the cannulated rail 561 and the guidewire570 combination, may thereafter be proximally withdrawn, leaving thelarge bore catheter 560 in position to direct a procedure catheter suchas any of the aspiration catheters disclosed elsewhere herein to thetarget site.

Referring to FIG. 22, the large diameter (LD) catheter 560 may in somesituations have a smaller diameter (SD) catheter though its centrallumen for the purposes of introducing an additional functionality (e.g.,clot grabber catheter 562, imaging catheter 10, or mechanicalthrombectomy tool 66) and/or telescoping the SD catheter to more distallocations in the anatomy. In order to enable delivery of the LD catheter560 and SD catheter as a single system, the SD catheter may have a coredilator 568 for support, and the gap between the outer diameter of theSD catheter and inner diameter of the LD catheter 560 may be maintainedor supported by a second, tubular dilator 571. The tubular dilator 571may have a shaped distal tip 572 for a smooth tapered transition fromthe SD catheter 541 to the LD catheter 540. The distal end 534 of thecore dilator may be provided with a complementary taper to the distaltaper of the thin wall SD dilator (FIG. 23) or may end at the distal endof the LD catheter (FIG. 24).

The core dilator 568 inside the SD catheter 541 and tubular dilator 570between the two catheters may have an interlocking feature to create asingle (SD+LD) catheter+(core+tubular) dilator system. For example,complementary connectors may be provided on hubs on the proximal ends ofthe system components.

Referring to FIG. 24, the tip of the tubular dilator 570 may beconfigured to taper to the guidewire lumen 576, thus covering andextending distally beyond the small diameter catheter 541 if it is inplace. The tip of the tubular dilator 570 may be provided with alongitudinally extending slit 578, scored or perforated one or moretimes to allow the tip to split longitudinally and be pulled back intothe space between the LD and SD catheters and fully expose the distalend of the small diameter catheter 541. See FIG. 25.

The single (SD+LD) catheter+(core+tubular) dilator system may bepre-assembled and detachably interlocked at the proximal hub. Additionaltubular dilators having a series of outside diameters and wallthicknesses may be provided such that the SD catheter may be used incombination with different diameter LD catheters. A LD catheter may beused with different SD catheters by providing tubular dilators havingthe same OD but a series of different inside diameters. The core+tubulardilators may simply be pulled proximally to withdraw both dilators as asingle system, or the tubular dilator may be configured with a tab orhandle at the proximal end and a slit, scoring, perforation or othermechanism so as to split, peel, or tear it along the longitudinal axisduring withdrawal to allow the tubular dilator to peel from the SDcatheter as it slides proximally out of the space between the LD and SDcatheters. (FIG. 25).

EXAMPLE EMBODIMENTS

An aspiration system with accelerated response, comprising one or moreof the following:

an aspiration pump in communication with a first chamber;

an aspiration catheter configured for placement into fluid communicationwith the first chamber by way of an aspiration tube;

a second chamber in between the aspiration tube and the catheter; and

a valve between the second chamber and the aspiration catheter;

wherein upon opening of the valve with negative pressure in the firstand second chambers, resistance to fluid flow between the second chamberand the distal end of the catheter is less than the resistance to fluidflow between the second chamber and the first chamber, causing a rapidaspiration into the second chamber.

An aspiration system as described in any embodiment herein, furthercomprising a handle on the aspiration catheter, and the second chamberis carried by the handle.

An aspiration system as described in any embodiment herein, furthercomprising a first control on the handle for opening the valve.

An aspiration system as described in any embodiment herein, wherein thevalve is normally closed and actuation of the control momentarily opensthe valve.

An aspiration system as described in any embodiment herein, furthercomprising a second control for activating the pump.

An aspiration system as described in any embodiment herein, furthercomprising a hemostasis valve carried by the handle.

An aspiration system as described in any embodiment herein, wherein thehemostasis valve comprises a collapsible tubular sidewall defining avalve lumen, and a filament formed into a loop around the tubularsidewall and configured to collapse the valve lumen.

An aspiration system as described in any embodiment herein, wherein thehemostasis valve further comprises a frame and a lever, and the filamenthas at least a first tail portion extending away from the loop, around afirst fulcrum on the lever and is secured against axial movement withrespect to the frame.

An aspiration system as described in any embodiment herein, wherein thefirst tail portion is connected to the frame.

An aspiration system as described in any embodiment herein, furthercomprising a second lever, and the filament further comprises a secondtail portion extending from the loop, around a second fulcrum on thesecond lever and is connected to the frame.

An aspiration system as described in any embodiment herein, wherein theaspiration tube is at least about 50 inches long.

An aspiration system as described in any embodiment herein, wherein thesecond chamber is configured to capture clot aspirated by the catheter.

An aspiration system as described in any embodiment herein, wherein atleast a portion of the second chamber is removably carried by thehandle.

An aspiration system as described in any embodiment herein, wherein thesecond chamber comprises a filter membrane spaced apart from atransparent wall.

An aspiration system as described in any embodiment herein, comprising atubular filter membrane, spaced radially inwardly apart from atransparent outer tubular wall.

An aspiration system as described in any embodiment herein, furthercomprising an operator actuated control, configured to toggle a flowregulator between a default low flow mode, and a momentary, operatorinitiated high flow override mode.

An aspiration system as described in any embodiment herein, wherein thesecond chamber is configured for location within a sterile field, andthe first chamber is configured for location outside of the sterilefield.

An aspiration system as described in any embodiment herein, furthercomprising a handle on the aspiration catheter, a tube between thehandle and the second chamber, and the tube is no more than about 20inches long.

A split dilator aspiration system, comprising one or more of thefollowing:

a catheter, having an elongate, flexible tubular body with a proximalend, a distal end, a side wall defining a central lumen, and a handle onthe proximal end; and

a dilator, advanceable through the central lumen, the dilator having anelongate body, cannulated to receive a guidewire, and an axiallyextending split along at least a portion of the elongate body,configured to allow removal of a portion of the dilator laterally fromthe guidewire.

A split dilator aspiration system as described in any embodiment herein,wherein the handle comprises a first engagement surface, and the dilatorhas a proximal hub with a second engagement surface configured to engagethe first engagement surface to releasably secure the dilator within thecatheter.

A split dilator aspiration system as described in any embodiment herein,comprising a retention clip carried by the proximal end of the catheterhandle.

A split dilator aspiration system as described in any embodiment herein,further comprising a retention surface carried by the grip body.

A split dilator aspiration system as described in any embodiment herein,wherein the retention surface is on a retention ring configured toengage the retention clip.

A split dilator aspiration system as described in any embodiment herein,further comprising a release control, for disengaging the grip body fromthe catheter handle.

A split dilator aspiration system as described in any embodiment herein,wherein the release control comprises at least one push button.

A split dilator aspiration system as described in any embodiment herein,further comprising a clot container on the handle.

A split dilator aspiration system as described in any embodiment herein,further comprising a hemostasis valve on the handle.

A split dilator aspiration system as described in any embodiment herein,wherein the split comprises a weakening in the wall to permit theprogressive formation of a slit through the wall to allow lateral escapeof the guidewire.

A split dilator aspiration system as described in any embodiment herein,wherein the split comprises a pre formed slit completely through thewall.

A split dilator aspiration system as described in any embodiment herein,wherein the split extends to a distal endpoint spaced proximally apartfrom the distal end of the catheter.

A split dilator aspiration system as described in any embodiment herein,wherein the distal endpoint is spaced proximally apart within the rangeof from about 5 cm to about 40 cm from the distal end of the catheter.

A split dilator aspiration system as described in any embodiment herein,further comprising a proximal handle on the dilator.

A split dilator aspiration system as described in any embodiment herein,wherein the handle comprises a grip body having a first gripping surfaceand a guidewire exit port configured to direct a guidewire along thefirst gripping surface.

A split dilator aspiration system as described in any embodiment herein,wherein the body comprises a paddle shape with the first grippingsurface on a first side and configured to be held between a thumb andforefinger such that a guidewire can be pinned between the thumb and thefirst gripping surface.

A split dilator aspiration system as described in any embodiment herein,further comprising friction enhancing surface structures on the firstgripping surface.

A split dilator aspiration system as described in any embodiment herein,wherein the friction enhancing surface structures comprise a pluralityof ridges.

A hemostasis valve, comprising one or more of the following:

a support;

at least a first lever, pivotably carried with respect to the support;

a collapsible tubular sidewall defining a valve lumen carried by thesupport;

a filament formed into a loop around the tubular sidewall, the filamenthaving at least a first tail portion extending away from the loop to thefirst lever; and

a first spring configured to move the first lever in a direction thatpulls the first tail portion away from the tubular sidewall, reducingthe diameter of the valve lumen in response to reducing the diameter ofthe loop.

A hemostasis valve as described in any embodiment herein, furthercomprising a second lever pivotably carried with respect to the support.

A hemostasis valve as described in any embodiment herein, furthercomprising a second tail portion extending away from the loop and to thesecond lever.

A hemostasis valve as described in any embodiment herein, wherein thefirst tail portion, second tail portion and loop are one continuousfilament.

A hemostasis valve as described in any embodiment herein, furthercomprising a lubricious coating on the filament.

A hemostasis valve as described in any embodiment herein, wherein thelubricious coating comprises silicone oil.

A hemostasis valve as described in any embodiment herein, wherein thefirst and second levers are biased in a direction that places the firstand second tail portions under sufficient tension to reduce the diameterof the valve lumen and provide a seal around a device extending throughthe valve.

A hemostasis valve as described in any embodiment herein, wherein thefirst and second levers are biased in a direction that places the firstand second tail portions under sufficient tension to close the valve.

A hemostasis valve as described in any embodiment herein, wherein thefirst tail portion is attached to the first lever.

A hemostasis valve as described in any embodiment herein, wherein thefirst tail portion slidably extends around a first fulcrum on the firstlever, and is attached to the frame.

A hemostasis valve as described in any embodiment herein, wherein thesecond tail portion slidably extends around a second fulcrum on thesecond lever, and is attached to the frame.

A hemostasis valve as described in any embodiment herein, wherein thefirst and second fulcrums comprise pins.

A hemostasis valve as described in any embodiment herein, mounted on theproximal end of a catheter.

A hemostasis valve as described in any embodiment herein, furthercomprising a connector in communication with the valve lumen, configuredfor connection to a source of vacuum.

A vacuum aspiration system, comprising:

a housing;

a fluid flow path extending through the housing;

a first catheter in fluid communication with the flow path and aconnector configured to place a source of aspiration in communicationwith the flow path;

a clot container carried by the housing; and

a hemostasis valve in the housing, configured to receive a secondcatheter and direct the second catheter through the first catheter.

A vacuum aspiration system as described in any embodiment herein,further comprising a flow regulator, configured to regulate fluid flowthrough the flow path.

A vacuum aspiration system as described in any embodiment herein,wherein at least a portion of the clot container is removably carried bythe housing.

A vacuum aspiration system as described in any embodiment herein,wherein the clot container comprises a filter membrane spaced apart froma transparent wall.

A vacuum aspiration system as described in any embodiment herein,comprising a tubular filter membrane, spaced radially inwardly apartfrom a transparent outer tubular wall.

A vacuum aspiration system as described in any embodiment herein,further comprising an operator actuated control, configured to togglethe flow regulator between a default low flow mode, and a momentary,operator initiated high flow override mode.

A vacuum aspiration system as described in any embodiment herein,wherein the operator actuated control comprises a momentary control thatplaces the system into the high flow override mode only when actuated bythe operator.

A vacuum aspiration system as described in any embodiment herein,further comprising an on—off control which toggles between an off modeand the low flow mode.

A vacuum aspiration system as described in any embodiment herein,further comprising a side wall containing the flow path, and anoptically transparent window in the side wall.

A vacuum aspiration system as described in any embodiment herein,wherein the flow regulator comprises a variable constriction in the flowpath.

A vacuum aspiration system as described in any embodiment herein,wherein the flow regulator comprises a flexible flow path side wall andan actuator configured to compress the flexible side wall.

A vacuum aspiration system as described in any embodiment herein,comprising a flexible filament surrounding the side wall and at leastone lever configured to place the filament under tension and close thevalve by reducing the diameter of the side wall.

A vacuum aspiration system as described in any embodiment herein,further comprising at least one spring, biasing the lever in a directionthat closes the valve.

A vacuum aspiration system as described in any embodiment herein,wherein the flow regulator comprises a tubing having an inside diameterand length to provide a desired flow rate.

A vacuum aspiration system as described in any embodiment herein,wherein the low flow mode aspirates fluid at a rate of no more thanabout 10 cc/second and the high flow mode aspirates fluid at a rate ofat least about 15 cc/second in an unobstructed aspiration.

A vacuum aspiration system, comprising:

a housing;

a fluid flow path extending through the housing;

a first catheter in fluid communication with the flow path and aconnector configured to place a source of aspiration in communicationwith the flow path;

a flow regulator, configured to regulate fluid flow through the flowpath;

a first operator actuated control, configured to toggle the flowregulator between a default, low flow mode, and a momentary, operatorinitiated high flow override mode; and

a second operator actuated control, configured to turn the fluid flowoff.

A vacuum aspiration system as described in any embodiment herein,further comprising a port on the housing, in communication with thefirst connector and configured to guide a second catheter through thehousing and into and through the first catheter.

A vacuum aspiration system as described in any embodiment herein,further comprising a hemostasis valve carried by the housing, incommunication with the port.

A vacuum aspiration system as described in any embodiment herein,further comprising a reservoir carried by the housing, for receivingthrombus and blood retrieved through the first catheter.

A vacuum aspiration system as described in any embodiment herein,wherein the reservoir comprises a transparent tubular wall releasablycarried by the housing.

What is claimed is:
 1. A method of removing a vascular obstruction,comprising the steps of: transvascularly advancing a distal end of anaspiration catheter into proximity with an obstruction; activating a lowflow, detection mode of aspiration through the catheter; and thereafteractivating a momentary control to activate a high flow, aspiration modeof operation and draw obstructive material into the distal end of theaccess catheter.
 2. A method of removing a vascular obstruction as inclaim 1, wherein activating the momentary control enlarges a restrictionin a flow path between the aspiration catheter and a source of vacuum.3. A method of removing a vascular obstruction as in claim 1, comprisingadvancing the distal end of the aspiration catheter into proximity witha pulmonary embolism.
 4. A method of removing a vascular obstruction asin claim 1, comprising advancing the distal end of the aspirationcatheter into proximity with a deep vein thrombosis.
 5. A method ofremoving a vascular obstruction as in claim 1, comprising advancing thedistal end of the aspiration catheter into proximity with a peripheralarterial occlusion.
 6. A flow control for an aspiration catheter,comprising: a housing, defining a central cavity, and having a patientport, a manifold port and a filter port; a movable gate within thehousing having a flow path and configured to selectively place thepatient port in communication with the filter port, the patient port incommunication with the manifold port or the manifold port incommunication with the filter port.
 7. A flow control as in claim 6,wherein the movable gate comprises a cylindrical body having a firstport in communication with a second port by a flow path through thebody.
 8. A flow control as in claim 7, wherein the first port, thesecond port and a solid side wall are spaced about 120 degrees apartaround the circumference of the gate.
 9. An aspiration catheter,comprising: an elongate, flexible tubular body, having a proximal end, adistal end and a central lumen; a hemostasis valve on the proximal endof the catheter, the hemostasis valve comprising: a collapsible tubularsidewall defining a valve lumen in communication with the central lumen;a filament formed into a loop around the tubular sidewall, the filamenthaving at least a first tail portion extending away from the loop andconnecting to a first lever; and a first spring configured to move thefirst lever in a direction that pulls the first tail portion away fromthe tubular sidewall, reducing the diameter of the valve lumen inresponse to reducing the diameter of the loop.
 10. An aspirationcatheter as in claim 9, wherein the filament further comprises a secondtail portion extending between the loop and a second lever.
 11. Anaspiration catheter as in claim 10 wherein the first and second leversare biased in a direction that places the first and second tail portionsunder sufficient tension to reduce the diameter of the central lumen andprovide a seal around a secondary device extending through the valve.12. An aspiration catheter as in claim 10 wherein the first and secondlevers are biased in a direction that places the first and second tailportions under sufficient tension to close the valve.
 13. A method ofplacing a catheter comprising: advancing a catheter and cannulateddilator over a guidewire to an intravascular site; removing the dilatorwhile leaving the catheter and guidewire in place; wherein the removingstep comprises pulling a proximal portion of the dilator laterally offof the guidewire with the guidewire progressively passing through anaxially extending split in the dilator.
 14. A method as in claim 13,further comprising the step of unlocking the dilator from the catheterprior to the removing step.